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Old 08-01-2019, 07:43 PM   #1
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Join Date: Jan 2019
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400HP ISL Oil Pressure

Okay so I searched and searched and couldn't come up with a good answer. Everyone has a different engine, opinion or theory.... I have a 2004 Winnebago Vectra 40AD with the 400HP ISL Cummins. Even the factory brochure doesn't show the 400HP as an option for 2004 it only goes up to 350HP but that's beside the point. I go down to the storage yard and start it once every month or so and warm it up good when I'm not using it. It's still pretty new to me with about 51,000 miles on it but when I started it today I saw the oil pressure jump up to 80 PSI at idle with a cold engine. After a while is started slowly going down but even at 175-180 engine temp it still sat about 45 PSI at idle. At fast idle (1000 rpms) it was about 55-60. I'm not sure if I let it warm up enough at 175 degrees and maybe it would have gone down lower but it just seemed a little higher than I remember it. Can anyone verify what the oil pressure should be in this specific engine or comment what yours runs at? We are about to head out on a trip and I haven't changed the oil in quite some time but I don't have a lot of miles either. Service is scheduled after this trip but now I'm starting to worry a little. Thanks for any comments or advice!
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Old 08-03-2019, 07:48 AM   #2
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Location: Palm Desert So. Cal
Posts: 12
Maybe this link will help determine/answer your question. The post is from 2016.

oil pressure - iRV2 Forums

The last post has a link you will have to cut and past.

2004 Horizon 36GD Cat C7 330
So. Cal
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Old 08-07-2019, 07:50 AM   #3
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Good morning AW2647.
We also have a 2004 Vectra 40 AD with the Cummins 400 ISL engine.
When we start the engine, she immediately reaches for 600 Kpa (approx 87 psi), at idle, she is normally close to 310 kpa (45 psi); and she runs under load at about 450 kpa (65 psi). I once had a Cummins shop shut her down right after start because of "high" oil pressure until I told him that this was "normal" for my engine during my time with her. He felt better after she warmed up and started to decrease. Hope this helps
Daniel & Gloria
2004 Winnebago Vectra 40AD
Blue Ox & Wrangler
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Old 08-07-2019, 07:59 AM   #4
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sorry, forgot to mention, we have approx 126,000 miles or 203311 klms on the engine.
Daniel & Gloria
2004 Winnebago Vectra 40AD
Blue Ox & Wrangler
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Old 08-11-2019, 04:11 PM   #5
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Location: Gulf Coast, Alabama
Posts: 80
Pressure at start-up and idle is a function of several variables that can make individual responses unable to be compared number to number.

Oil pressure underway is a constant 55psi at 1500-1700RPM. 62,000 miles on the coach
Rick and Sandy
2003 American Eagle, 52K miles
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